God didn’t plan for there to be numerous denominations and factions among believers. When Paul received a revelation from God about his ministry, he was told that the Gentiles and Jews would be “of the same body” (Ephesians 3:6). “These words indicate the unique aspect of the mystery that was not previously known: the equality and mutuality that Gentiles had with Jews in the church, the one body. That Gentiles would turn to the God of Israel and be saved was prophesied in the OT (see Rom 15:9-12); that they would come into an organic unity with believing Jews on an equal footing was unexpected” (note on Ephesians 3:6).
Paul stated, “There is one body and one Spirit, just as you were called in one hope of your calling; one Lord, one faith, one baptism; one God and Father of all, who is above all, and through all, and in you all” (Ephesians 4:4-6, NKJV). Paul’s focus on the oneness of believers in Christ was likely meant to point out that there should be no distinctions between Christians. We are all saved and on our way to heaven. Everything else is a matter of individual belief, not the teaching of Jesus Christ. What Paul wanted the Ephesians to understand was that they were not a new or different religious group from the Jews. They were not supposed to be isolated from the Jewish churches, but integrated into them.
Paul’s description of believers as one body (Ephesians 4:4) emphasized the connectedness, the integration of the individual parts, and collective functioning that should be evident in Jesus’ followers. Paul talked about the edifying of the body of Christ and told the Ephesians, “that we should no longer be children, tossed to and fro and carried about with every wind of doctrine, by the trickery of men, in the cunning craftiness of deceitful plotting, but, speaking the truth in love, may grow up in all things into Him who is the head—Christ— from whom the whole body, joined and knit together by what every joint supplies, according to the effective working by which every part does its share, causes growth of the body for the edifying of itself in love” (Ephesians 4:14-16, NKJV).
The Greek word translated edifying, oikodome (oy-kod-om-ay’) has to do with architecture and refers to the structure by which something is perceived to be a building. When we think of the church as a building that we go to we are missing the point of what Paul was trying to say about how Jesus’ church should function. Believers are supposed to be joined by their faith and work together as a single unit that functions collectively to spread the gospel around the world. The key ingredient that you could say is the glue or mortar that holds everything together is love. The Greek word Paul used in Ephesians 4:16 is agape. Sometimes referred to as Christian love, agape signifies the kind of love that is derived from Christ.